It's more of an effort to get people to realize sharing documents/pictures is quick and easy. Although I'm sure everyone was already aware of online storage, I think the 250gb was just enough where users might decide they want a bit more online space...at a cost. It's really just a marketing strategy.
But I do like FileDropper. Rapidshare and MediaFire have become riddled with popups and ads. FileDropper is quick and easy on the eyes, even for free users.